content: /*
   * Copyright 2017 David Karnok
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package hu.akarnokd.reactive4javaflow.impl.operators;
  
  import hu.akarnokd.reactive4javaflow.*;
  import hu.akarnokd.reactive4javaflow.errors.CompositeThrowable;
  import hu.akarnokd.reactive4javaflow.functionals.*;
  import hu.akarnokd.reactive4javaflow.fused.ConditionalSubscriber;
  
  import java.util.Objects;
  import java.util.concurrent.Flow;
  
  /**
   * Maps each 'rail' of the source ParallelFolyam with a mapper function
   * and handle any failure based on a handler function.
   *
   * @param <T> the input value type
   * @param <R> the output value type
   * @since 2.0.8 - experimental
   */
  public final class ParallelMapTry<T, R> extends ParallelFolyam<R> {
  
      final ParallelFolyam<T> source;
  
      final CheckedFunction<? super T, ? extends R> mapper;
  
      final CheckedBiFunction<? super Long, ? super Throwable, ParallelFailureHandling> errorHandler;
  
      public ParallelMapTry(ParallelFolyam<T> source, CheckedFunction<? super T, ? extends R> mapper,
              CheckedBiFunction<? super Long, ? super Throwable, ParallelFailureHandling> errorHandler) {
          this.source = source;
          this.mapper = mapper;
          this.errorHandler = errorHandler;
      }
  
      @Override
      public void subscribeActual(FolyamSubscriber<? super R>[] subscribers) {
  
          int n = subscribers.length;
          @SuppressWarnings("unchecked")
          FolyamSubscriber<? super T>[] parents = new FolyamSubscriber[n];
  
          for (int i = 0; i < n; i++) {
              FolyamSubscriber<? super R> a = subscribers[i];
              if (a instanceof ConditionalSubscriber) {
                  parents[i] = new ParallelMapTryConditionalSubscriber<T, R>((ConditionalSubscriber<? super R>)a, mapper, errorHandler);
              } else {
                  parents[i] = new ParallelMapTrySubscriber<T, R>(a, mapper, errorHandler);
              }
          }
  
          source.subscribe(parents);
      }
  
      @Override
      public int parallelism() {
          return source.parallelism();
      }
  
      static final class ParallelMapTrySubscriber<T, R> implements ConditionalSubscriber<T>, Flow.Subscription {
  
          final FolyamSubscriber<? super R> actual;
  
          final CheckedFunction<? super T, ? extends R> mapper;
  
          final CheckedBiFunction<? super Long, ? super Throwable, ParallelFailureHandling> errorHandler;
  
          Flow.Subscription s;
  
          boolean done;
  
          ParallelMapTrySubscriber(FolyamSubscriber<? super R> actual, CheckedFunction<? super T, ? extends R> mapper,
                  CheckedBiFunction<? super Long, ? super Throwable, ParallelFailureHandling> errorHandler) {
              this.actual = actual;
              this.mapper = mapper;
              this.errorHandler = errorHandler;
          }
  
          @Override
          public void request(long n) {
              s.request(n);
          }
  
          @Override
          public void cancel() {
              s.cancel();
          }
  
          @Override
          public void onSubscribe(Flow.Subscription s) {
              this.s = s;
  
              actual.onSubscribe(this);
          }
  
          @Override
          public void onNext(T t) {
              if (!tryOnNext(t) && !done) {
                  s.request(1);
              }
          }
  
          @Override
          public boolean tryOnNext(T t) {
              if (done) {
                  return false;
              }
              long retries = 0;
  
              for (;;) {
                  R v;
  
                  try {
                      v = Objects.requireNonNull(mapper.apply(t), "The mapper returned a null value");
                  } catch (Throwable ex) {
                      FolyamPlugins.handleFatal(ex);
  
                      ParallelFailureHandling h;
  
                      try {
                          h = Objects.requireNonNull(errorHandler.apply(++retries, ex), "The errorHandler returned a null item");
                      } catch (Throwable exc) {
                          FolyamPlugins.handleFatal(exc);
                          cancel();
                          onError(new CompositeThrowable(ex, exc));
                          return false;
                      }
  
                      switch (h) {
                      case RETRY:
                          continue;
                      case SKIP:
                          return false;
                      case STOP:
                          cancel();
                          onComplete();
                          return false;
                      default:
                          cancel();
                          onError(ex);
                          return false;
                      }
                  }
  
                  actual.onNext(v);
                  return true;
              }
          }
  
          @Override
          public void onError(Throwable t) {
              if (done) {
                  FolyamPlugins.onError(t);
                  return;
              }
              done = true;
              actual.onError(t);
          }
  
          @Override
          public void onComplete() {
              if (done) {
                  return;
              }
              done = true;
              actual.onComplete();
          }
  
      }
      static final class ParallelMapTryConditionalSubscriber<T, R> implements ConditionalSubscriber<T>, Flow.Subscription {
  
          final ConditionalSubscriber<? super R> actual;
  
          final CheckedFunction<? super T, ? extends R> mapper;
  
          final CheckedBiFunction<? super Long, ? super Throwable, ParallelFailureHandling> errorHandler;
  
          Flow.Subscription s;
  
          boolean done;
  
          ParallelMapTryConditionalSubscriber(ConditionalSubscriber<? super R> actual,
                  CheckedFunction<? super T, ? extends R> mapper,
                  CheckedBiFunction<? super Long, ? super Throwable, ParallelFailureHandling> errorHandler) {
              this.actual = actual;
              this.mapper = mapper;
              this.errorHandler = errorHandler;
          }
  
          @Override
          public void request(long n) {
              s.request(n);
          }
  
          @Override
          public void cancel() {
              s.cancel();
          }
  
          @Override
          public void onSubscribe(Flow.Subscription s) {
              this.s = s;
  
              actual.onSubscribe(this);
          }
  
          @Override
          public void onNext(T t) {
              if (!tryOnNext(t) && !done) {
                  s.request(1);
              }
          }
  
          @Override
          public boolean tryOnNext(T t) {
              if (done) {
                  return false;
              }
              long retries = 0;
  
              for (;;) {
                  R v;
  
                  try {
                      v = Objects.requireNonNull(mapper.apply(t), "The mapper returned a null value");
                  } catch (Throwable ex) {
                      FolyamPlugins.handleFatal(ex);
  
                      ParallelFailureHandling h;
  
                      try {
                          h = Objects.requireNonNull(errorHandler.apply(++retries, ex), "The errorHandler returned a null item");
                      } catch (Throwable exc) {
                          FolyamPlugins.handleFatal(exc);
                          cancel();
                          onError(new CompositeThrowable(ex, exc));
                          return false;
                      }
  
                      switch (h) {
                      case RETRY:
                          continue;
                      case SKIP:
                          return false;
                      case STOP:
                          cancel();
                          onComplete();
                          return false;
                      default:
                          cancel();
                          onError(ex);
                          return false;
                      }
                  }
  
                  return actual.tryOnNext(v);
              }
          }
  
          @Override
          public void onError(Throwable t) {
              if (done) {
                  FolyamPlugins.onError(t);
                  return;
              }
              done = true;
              actual.onError(t);
          }
  
          @Override
          public void onComplete() {
              if (done) {
                  return;
              }
              done = true;
              actual.onComplete();
          }
  
      }
  }
  